State and local fire marshals are attempting to determine the cause of a fast-moving Monday morning fire that destroyed a former commercial building that was home to a church and two small businesses.

The building, located at 119 Commerce Ave., contained the Tabernacles of Grace Chapel, the Lucky Dog pet grooming business and a small machine shop, according to Danielson Fire Chief Gerry Marcheterre. Town assessment records also indicate companies identified as Engineered Shims or Solutions and Moldvision were tenants in the building.

For many years, the building housed the Barrette Electric Co.

Coincidentally, Marcheterre said, the pet grooming business was previously located in a former agricultural supply store that was extensively damaged by fire last year.

Firefighters from eight companies spent about 3 ½ hours battling the blaze, which was reported at 8:10 a.m. and quickly engulfed the large building.

Marcheterre said the first firefighters on the scene encountered thick smoke coming from the building. A team of firefighters who entered the building opened an overhead door and found that part of the building was a mass of flames.

“They tried to extinguish the fire, but it got up into the attic over their heads, and we had to pull them out of the building for their own safety,” he said.

Marcheterre said a crew was also put on the roof of the building to cut a hole to ventilate the fire in the attic.

“No sooner had they cut the hole when we had to evacuate them because the roof was beginning to collapse,” Marcheterre said.

Firefighters fought the fire from the exterior, including using large-capacity hoses off two ladder trucks to douse the flames.

Marcheterre said the building was a total loss. No firefighters were injured fighting the blaze, he said.

The fire also knocked out electrical service to residences and businesses in a large section of the downtown business district from about 9:30 a.m. to 11 a.m. Killingly Town Manager Bruce Benway he heard a transformer had malfunctioned and had to be replaced before the power could be restored.

Betti Kuszaj, executive director of the Northeastern Connecticut Chamber of Commerce, could see the fire from her office at 3 Central Street.

“There was really thick black smoke coming from the fire, and we could see flames shooting at least 20 feet, maybe higher, above the roof of the building,” Kuszaj said.

She said she could see crews from the two aerial ladder trucks pouring water into the burning building.

Firefighters from the Danielson Fire Department were being assisted by crews from the Dayville, Williamsville (Rogers), East Brooklyn, Attawaugan, Moosup and Atwood Hose (Wauregan) departments. Dispatchers said an ambulance was also put on standby at the scene.